Supported Planar Single and Multiple Bilayer Formation by DOPC Vesicle Rupture on Mica Substrate: A Mechanism as Revealed by Atomic Force Microscopy Study

Abstract

A planar lipid bilayer on a solid support serves as model system that explains fundamental aspects of membrane biology and enables us to characterize wide-range surface-sensitive techniques, including molecular engineering. The present study aims at understanding the process of single and multiple bilayer formation after the exposure of small unilamellar vesicles (SUVs) of dioleoyl phosphatidylcholine (DOPC) to mica substrate. Isolated single bilayer formation and co-existence of double and triple lipid bilayers in the aqueous medium have been quantitatively measured by atomic force microscopy and discussed the physicochemical mechanism. It has been observed that due to the strong adhesion of DOPC SUV to mica surface, vesicles of diluted solution rupture spontaneously and form isolated bilayer patches when they come in contact with the mica surface. No further lateral growth or movement of the bilayer patches has been observed upon increase of incubation time. However, the increase of vesicle number on the same surface area by successive deposition of DOPC solution of same concentration and increasing incubation time shows merging of the nearby patches as well as development of stacked second and third bilayers due to edge-guided rupture of adsorbed vesicles on first or second bilayer patches. Mechanisms of single and multi-bilayer formation and a theoretical interpretation of the process have been elucidated.

Cholesterol Effect on the Specific Capacitance of Submicrometric DOPC Bilayer Patches Measured by in-Liquid Scanning Dielectric Microscopy

“…The membrane patches along the profile are ∼4.2 nm thick (see also histogram analysis in Supporting Information S1). This value is in agreement with thickness values reported for solid-supported DOPC patches by AFM (∼4.2 nm) and quantitative differential interference contrast microscopy (qDIC) (∼4.1 nm) and slightly smaller than the steric thickness measured on unilamellar vesicles by small angle neutron scattering (SANS) or small angle X-ray scattering (SAXS) , (∼5 nm). The lateral sizes of the patches range from a few micrometers down to ∼200 nm.…”

Asymmetric Lipid Membranes under Shear Flows: A Dissipative Particle Dynamics Study

“…Employing a pulsed-jet method, Kamiya et al have produced nano-sized asymmetric lipid vesicles, which are produced by asymmetric planar lipid bilayers by applying longer duration and higher pressure pulsed-jet flows, rather than those used to form micro-sized lipid vesicles [ 19 ]. At present, many studies on asymmetric lipid bilayers have also been published [ 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. For example, by the vesicle fusion technique on mica, Seeger et al have assembled the supported lipid bilayers and the influence of different physical parameters on the main phase transition have also been clarified [ 8 ].…”

Accurate Wide-Modulus-Range Nanomechanical Mapping of Ultrathin Interfaces with Bimodal Atomic Force Microscopy

“…Chiodini et al used lipid bilayers to apply bottom-effect corrections to FDCs . Lipid bilayers are of relevance in cell biology and biotechnology. − …”

“…50 μL of the suspension was deposited into a freshly cleaved muscovite mica disk (Grade V-1, Alpha Biotech) and incubated for 60 min in a closed container to avoid evaporation. To favor the formation of a double bilayer, we added 50 μL of the DPPC solution every 15 min . After deposition, the sample was carefully rinsed with imaging buffer (10 mM Tris, 100 mM NaCl, pH 7.4).…”

“…To favor the formation of a double bilayer, we added 50 μL of the DPPC solution every 15 min. 69 After deposition, the sample was carefully rinsed with imaging buffer (10 mM Tris, 100 mM NaCl, pH 7.4). The sample was placed inside a fluid chamber.…”